VoiceReceiverAdapter.java: add default missing doc (#1371)

* VoiceReceiverAdapter.java: add default missing doc

Signed-off-by: Chris Sdogkos <work@chris-sdogkos.com>

* docs(VoiceReceiverAdapter): improve message

Write an improved, more specific JavaDoc for VoiceReceiverAdapter.

Signed-off-by: Chris Sdogkos <work@chris-sdogkos.com>

---------

Signed-off-by: Chris Sdogkos <work@chris-sdogkos.com>

Author: christolis

application/src/main/java/org/togetherjava/tjbot/features/VoiceReceiverAdapter.java

@@ -8,6 +8,13 @@
 
 import java.util.regex.Pattern;
 
+/**
+ * Adapter implementation of a {@link VoiceReceiver}. A new receiver can then be registered by
+ * adding it to {@link Features}.
+ * <p>
+ * {@link #onVoiceUpdate(GuildVoiceUpdateEvent)} like the other provided methods can be overridden
+ * if desired. The default implementation is empty, the adapter will not react to such events.
+ */
 public class VoiceReceiverAdapter implements VoiceReceiver {
 
     private final Pattern channelNamePattern;